Reversible-speed pulley.



F. M. CHAPMAN,

REVERSIBLE SPEED PULLEY.

APPLICATION FILED OCT. 15. 1912.

1, 1 56, 132. Patented Oct. 12, 1 915.

2 SHEETSSHEET I.

WITNESSES INVENTOH,

CDLUMBIA ILANDGRAFH COHWASHINOTDN. 0 c7 F. M. CHAPMAN.

REVERSIBLE SPEED PULLEY.

APPLICATION FILED OCT. 15 1912.

1,156,132. Pate med Oct. 12, 191 5.

2 SHEETS-SHEET 2.

H nt" WITNESSES INVENTOR! ATTORNEYS COLUMBIA PLANOURAPH CO.,W ASHINGTOND. c.

marten srArns meme onrren.

FRANK M. CHAPMAN, OF.FORT EDWARD, NEW YORK, ASSIGNOR OF THBEE-EIGHTHS TOFIR-ED A. BRATT AND THREE-EIGHTHS TO ROBERT MoWI-IORTER, 013 FORT.

EDWARD, NEW YORK.

REVERSIBLE-SPEED PULLEY.

Specification of Letters Patent. Patented Get. 12, 1%15.

Application filed October 15, 1912. Serial No. 725,776.

To all whom it may concern:

Be it known that I, FRANK M. CHAPMAN, a citizen of the United States,residing at Fort Edward, county of lVashington, State of New York, haveinvented certain new and useful Improvements in Reversible- SpeedPulleys; and I do hereby declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same.

The invention relates to the general class of rotary change speeddevices, and is particularly directed to the attainment of a simple andefficient organization whereby the speed of a shaft may be varied fromzero throughout a wide range of speeds in one or both directions.

The invention primarily consists in employing a differentialgearinghaving one of its three essential elements positively connected with theshaft, another of said elements driven directly from the driver, and thethird of said elements being driven by one of the two cooperatingmembers of a variable friction driving mechanism, the other member ofwhich friction driving mechanism is driven from the driver.

-The invention further consists (1) in so correlating the severalelements of the organization that the torque brought to bear upon thepoint of frictional contact of the variable friction driving mechanismis but a fraction ofthe torque brought to bear upon the other elementsof the differential combicertain details of construction and arrangementhereinafter described, and set forth in the claims appended hereto.

I have illustrated an embodiment of my invention in the accompanyingdrawings, in which Figure l is a longitudinal sectional view, taken inthe plane of mounting of a driven shaft; Fig. 2 is a section, taken online 22 of Fig. 1, showing a main'driven pulley and its containedmechanism in elevation; Fig. is a sectional detail, on lines 33 of Figs.1 and 2; and Fig. 4: is a plan illustrating the assembly of the completedevice, in connection with a driving shaft and a driven shaft.

Referring to the drawings, a main belt A. is mounted upon a pulley Bfast upon a driving shaft C, and a pulley D loose upon a driven Shaft E.Within the inclosure of the pulley D a worm gear F is mounted fast uponthe driven shaft E. Two worms G, G are mounted in bearings g in abox-like structure H integral with and projecting from the spokes of thepulley D. The worms G, G are mounted upon opposite sides of and engagewith the worm gear F. Attention is called at this point to the fact thatif no provision were made for turning the wormsG, G and power were nowapplied to the driving shaft, the belt A would rotate the pulley D, and,as the pitch of the worms G, G is not sufficient to cause them to turnwhen they engage worm gear. F fast on the driven shaft E, the powerwould be applied to the driven shaft E as would be the case if thepulley D were fast upon the driven shaft E. v

The axes of the worms G, G project beyond the bearings g at one end ofthe box H, and upon these projecting ends spur gears J, J aremountedfast. A shaft K is mounted in a bearing is in the'rim of thepulley D, and in a second bearing 70' projecting from a cover 72, of thebox H. A pinion L mounted fast on the shaft K meshes with both of thespur-gears J, J, so that these gears and the worms G, G driven therebymust rotate in the same direction. This be ing the case, in order thatthe worms G, G

may turn the worm gear F, one of these worms must have a right-handspiral thread and the other a left-hand spiral thread. A frictionface-plate M is mounted for l0ngitudinal movement upon the shaft K, anda feather (3, engaging both the shaft K and the hub of the face-plate M,transmits the rotation of the faceplate M to the shaft K, whilepermitting of the longitudinal movcment of the face-plate M upon theshaft K.

A compression spring 1? surrounding the shaft K and bearing againstthebearing 7c and the hub of the faceplate M, tends to force said plateM longitudinally upon the shaft K toward the axis of the pulley D. Acollar 22 on the shaft K limits this movement of the plate ll by thespring P. pulley Q; is mounted loose upon the shaft and is preventedfrom .moving longitud 1- nally thereon by collars o. The pulley isprovided with a plurality of longitud nal holes through which featherrods 1" pro]ect inn; from a friction wheel R are adapted to slide.

The friction wheel R is mounted loose upon the driven shaft E and theface-plate M is held in contact with the periphery of this wheel R bythe spring P. A cl1anneled collar S is mounted loosely upon the shaft Eand is secured to the feather rods 1" serving to move the friction wheelR toward or from the axis of the face-plate M. A lever S engaging thegroove in the channeled collar .9 provides means for moving the frictionwheel R toward and from the axis of the face-plate M during rotation ofthe device.

The friction disk M is ordinarily held in contact with the periphery ofthe friction Wheel R by the spring P. The friction wheel B may, however,be moved axially along the shaft E until it is entirely free of the diskM. In this free position of the friction wheel R the shaft E is directlyconnected to the pulley D, as the worms G do not revolve and the wholeof the power transmitted to the shaft E is applied through the pulley D.

When the fast run friction wheel R is brought into contact with thefriction disk M near the periphery of the latter, the friction disk M isrevolved at its slowest speed and turns the worms G in, a direction topermit the shaft E to rotate somewhat slower than the pulley D. As thefriction wheel R is moved nearer to the center of the disk M the wormsare revolved at a higer rate of speed, and the shaft E runs yet moreslowly until the friction wheel R reaches a point about midway of theradius of the disk M, when the worms G will be revolved at a sufiicientspeed to permit the shaft E to be stationary.

At all of those positions of the friction wheel R, between the peripheryof the disk M and the position midway of the radius of this disk whereno movement of the shaft E is attained, it will be seen that thevariable friction driving mechanism has only been employed to back theworms off against the drive of the pulley D. then this midway positionof the friction wheel R is passed and the point of engagement approachesthe center of the disk M, the speed of the worms is increased and theshaft E is rotated in the opposite direction. As the speed of thefriction wheel R is much greater than the attainable speed of the shaftE the torque exerted at the point of contact between the friction WheelR, the friction disk M never approaches the torque required to drive theshaft E direct.

It will be obvious that the pulleys D and (,1 may be connected by gearsto run at the requisite speeds should be a belted arrange ment beundesirable. It will also be obvious that the pulley Q, need not berotated when the desired range of speeds will admit of an arrangement bywhich the speed of the friction disk M produced by its movement aboutthe stationary friction Wheel B will attain the desired result.

That I claim is:

l. A change speed device comprising a shaft, a gear connected directlyto said shaft and constituting one of the elements of a differentialmechanism, a friction wheel mounted for axial movement and rotationupon. said shaft and constituting a second element of said difi'erentialmechanism, a main driving member loosely mounted upon said shaft, afriction disk mounted upon said main driving member, said friction diskbeing engaged with the periphery of said friction wheel, and gearingconnecting said friction disk to said gear, said main driving member,said friction disk and said gearing constituting the third element ofsaid differential mechanism; substantially as described.

2. A change speed device comprising a differential mechanism, a shaft,one element of said differential mechanism being connected directly tosaid shaft, a second element of said differential mechanism which isrotatable upon said shaft, a friction disk carried by said secondelement of said differ ential mechanism and geared to said firstelement, and a third element of said differential mechanism consistingof a friction wheel axially movable upon said shaft and having itsperiphery engaged with said friction disk; substantially as described.

3. The combination with a shaft, of a gear fast on said shaft, a pulleyloosely mounted on said shaft, a friction disk mounted for rotationwithin said pulley, a gear train connecting said friction disk with saidgear on said shaft, said friction disk axially upon said shaft;substantially as 10 having its face lying parallel to said shaft,described.

a second pulley mounted for rotation upon In testimony whereof I afiixmy signature, said shaft, a friction Wheel mounted for in presence oftwo Witnesses.

longitudinal and rotary movement upon FRANK M CHAPMAN said shaft anddriven from said second pulley, said friction Wheel being designed forWitnesses:

engagement With the surface of said disk, FRED A. BRATT.

and means for moving said friction Wheel C. E. BEERS.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

- Washington, D. 0.

